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With the innovation of electronics industry and the advancement in 5G technology, the overheating problem has become an urgent obstacle to further realize the high performance and multi-function of electronic devices. Thus, it is essential to develop efficient thermal management materials to realize timely and effective heat dissipation. The thermal management systems based on phase change materials (PCMs) have received extensive attention in recent years. In this work, composite PCMs with a high phase change enthalpy of 149.56 J g−1, multiple phase change characteristics, a high thermal conductivity of 1.28 Wm−1 K−1, and excellent shape stability were fabricated by the means of cross-linked polymer swelling strategy. When the as-prepared composite PCMs were directly attached to the heating plate or served as thermal interface materials (TIMs) to dissipate heat, the temperature of heating plate can be reduced by 5.8 °C and 18.8 °C, respectively, revealing great potential in the thermal management application of electronic devices.

As is well known, titanium alloy precipitates when subjected to aging treatment, which poses great influence on its mechanical properties. Thus, solution and solution-aging treatments were conducted in this work, and the wear performance was investigated under different normal loads. The results showed that acicular α′ martensite in the original selective laser melted Ti–6Al–4V was decomposed into α + β phases after the solution treatment, and then Ti3Al nanoparticles clusters were further formed in the α-matrix after the solution-aging treatment. The coefficient of friction decreased straightly as the normal load was increased from 20 to 100 N, and the wear mechanisms were characterized by abrasion, adhesive and oxidative wears. The wear rate of solution and solution-aging treated samples increased significantly comparing to the as-built counterpart, but the increment of the solution-aging treated sample was smaller than that of the solution-only treated sample, because of the Ti3Al precipitation in the solution-aging treated sample. These particles provided ball-like effect, reduced material losses and stabilized the wear process. All these factors contributed to the improvement in wear properties of the parts made by selective laser melting.

Recent years have witnessed a booming interest in grid-scale electrochemical energy storage, where much attention has been paid to the aqueous zinc ion batteries (AZIBs). Among various cathode materials for AZIBs, manganese oxides have risen to prominence due to their high energy density and low cost. However, sluggish reaction kinetics and poor cycling stability dictate against their practical application. Herein, we demonstrate the combined use of defect engineering and interfacial optimization that can simultaneously promote rate capability and cycling stability of MnO2 cathodes. β-MnO2 with abundant oxygen vacancies (VO) and graphene oxide (GO) wrapping is synthesized, in which VO in the bulk accelerate the charge/discharge kinetics while GO on the surfaces inhibits the Mn dissolution. This electrode shows a sustained reversible capacity of ~ 129.6 mAh g−1 even after 2000 cycles at a current rate of 4C, outperforming the state-of-the-art MnO2-based cathodes. The superior performance can be rationalized by the direct interaction between surface VO and the GO coating layer, as well as the regulation of structural evolution of β-MnO2 during cycling. The combinatorial design scheme in this work offers a practical pathway for obtaining high-rate and long-life cathodes for AZIBs.

In comparison with the common-used electron donor (D)-electron acceptor (A) type symmetric polymers with regular structures, their asymmetric counterparts have received much less attention and seldom been applied in polymer solar cells. Since the precise modulation of π bridge can significantly influence the photoelectric properties of D-A type polymers, π bridges of tailorable thiophenes are introduced into benzodithiophene (BDT)-benzodithiophene-4,8-dione (BDD) copolymers in both symmetric and asymmetric patterns. Together with the halogen substituent of fluorine or chlorine on BDT, four polymer donors are designed and synthesized. As expected, PTB2T-F and PTB2T-Cl with the asymmetric π bridges of thiophene and hexyl-bithiophene exhibit better planarity, stronger intermolecular interaction and higher hole mobility than P2TB2T-F and P2TB2T-Cl with the symmetric π bridges of hexyl-bithiophene. The more suitable phase separation and optimized nanomorphology is determined by the reasonable miscibility between asymmetric polymer and acceptor, which is evaluated by Flory-Huggins interaction, contributing to the extremely higher performance than that of symmetric counterpart. Moreover, paired with IT-4F as the acceptor, PTB2T-F affords better device performances than the reference BDT-BDD polymer PM6 with the symmetry π bridge of thiophene. These results demonstrate that the precise modulation of asymmetric π bridges is a promising strategy to construct high-efficiency D-A type polymer donors.

To increase the service life of rechargeable batteries, transition metal oxide hosts with high structural stability for the intercalation of carrier ions are important. Herein, we reconstruct the crystal structure of a commercial V2O5 by pre-intercalating H+ and H2O pillars using a facile hydrothermal reaction and obtain a bi-layer structured H0.642V2O5·0.143H2O (HVO) as an excellent host for aqueous Zn-ion batteries. Benefiting from the structural reconstruction, the irreversible “layer-to-amorphous” phase evolution during cycling is considerably less, resulting in ultra-high cycling stability of HVO with nearly no capacity fading even after 500 cycles at a current density of 0.5 A g−1. Moreover, a synthetic proton and Zn2+ intercalation mechanism in the HVO host is demonstrated. This work provides both a facile synthesis method for the preparation of V-based compounds and a new viewpoint for achieving high-performance host materials.

This paper mainly investigates the slamming dynamic response and progressive damage evolution of the composite lattice sandwich structure under different slamming velocities and deadrise angles. Based on the Coupled Eulerian–Lagrangian (CEL) method, an integrated numerical model of sandwich structures is developed to simulate the slamming process, in which the progressive damage evolution of composite material is considered with VUMAT subroutine. The reliability and accuracy of the corresponding numerical models are verified through the comparison between numerical and experimental results. Then, the typical slamming behavior of composite lattice sandwich structure is analyzed in detail, including hydrodynamic force, jet flow/water pressure distribution, progressive damage evolution and absorption energy. Subsequently, the influences of slamming velocity and deadrise angle on the hydrodynamic response and damage modes of the sandwich structures are investigated based on the developed numerical models. The results demonstrate that the slamming velocity and deadrise angle have significant influences on the hydroelastic behavior and damage modes of composite lattice sandwich structures. In the process of slamming, matrix damage and delamination damage are more prone to appear in the chine region, while the fiber damage more likely occurs under the higher slamming velocity and lower deadrise angle cases.

This paper aims to evaluate the dynamic response and failure mechanism of corrugated core composite metal sandwich structures under the complicated fluid-structure interaction. Firstly, a reliable ...

Projectiles made of reactive structure materials (RSM) can damage the target with not only kinetic but also chemical energy, but the enhanced damage potential of RSM may become compromised if extreme loading condition disintegrates the projectile before the target is reached. In this work, a ductile coating of Ni was introduced to a tungsten-zirconium (W-Zr) alloy, a typical brittle RSM, to preserve the damage potential of the projectile. Detonation driving tests were carried out with X-ray photography and gunpowder deflagration driving tests were carried out with high-speed photography for the coated and uncoated RSM samples, respectively. The craters on the witness target were analyzed by scanning electron microscopy and X-ray diffraction. The Ni coating was found to effectively preserve the damage potential of the W-Zr alloy under extreme loading conditions, whereas the uncoated sample fractured and ignited before impacting the target in both detonation and deflagration driving. The crack propagation between the reactively brittle core and the ductile coating was analyzed based on the crack arrest theory to mechanistically demonstrate how the coating improves the structural integrity and preserves the damage potential of the projectile. Specifically, the Ni coating envelops the W-Zr core until the coated sphere penetrates the target, and the coating is then eroded and worn to release the reactive core for the projectile to damage the target more intensively.

In this article, a long-wave infrared InAs/GaAs sub-monolayer quantum dot quantum cascade photodetector (SML QD-QCD) grown on GaAs substrate is demonstrated. Temperature- and excitation-dependent photoluminescence measurements are used to study the optical properties of the quantum dot active region, which reveal energetically hybrid ground states between the InAs quantum dot and InGaAs quantum well due to the possible inter-mixing of In and Ga atoms during growth process. The device covers a spectral region from 6.5 to 9 μm. At 77 K, a peak responsivity of 7.5 mA/W is found at 8.3 μm (0 V) and a zero-bias differential-resistance-area ( R0A ) product of 9008 Ω·cm2 is obtained. The white noise-limited detectivity is 6.5 × 109 cm·Hz1/2/W. These results encourage the SML QD-QCD as a strong competitor for long-wave infrared imaging applications that require normal incidence and low power dissipation.

A wideband terahertz (THz) output network consisting of a pyramidal horn and a diamond Brewster window has been developed for 0.7–1.0-THz traveling-wave tube (TWT) amplifier and is measured at 0.325–0.5 THz owing to the limitation of the measurement facility. A pyramidal horn is designed to convert the waveguide mode into a high-purity quasi-plane polarized mode to meet the demand of the Brewster window. A diamond Brewster window plate with low THz transmission loss is fabricated via chemical vapor deposition (CVD). The plate is directly placed on the pyramidal horn with a Brewster angle. A circular window plate supporter is intended to balance the stress distribution during diamond-metal brazing. The measurement shows transmission coefficient is better than 0.85 within a wide bandwidth of 0.325–0.5 THz. This letter provides a practical way for a single diamond window structure for THz TWT amplifiers.

A new flame retardant, DM/PEI/MWCNT, was prepared by self-assembly method based on non-covalent interactions between hydroxyl and amino groups on the surface of hydroxyl multi-walled carbon nanotubes (MWCNT), polyethyleneimine (PEI) and diatomite (DM). The flame-retardant composites were prepared by adding DM/PEI/MWCNT to room-temperature vulcanisated silicone rubber (RTV-silicone). The structure of the flame retardant and composites was characterised by polarising light microscope, scanning electron microscopy and Fourier-transform infrared spectroscopy. The flame retardancy of composites was studied by limited oxygen index and cone calorimeter measurement. Results showed that RTV-silicone composites with DM/PEI/MWCNT owned better flame retardancy. In addition, DM/PEI/MWCNT exhibited better compatibility in silicone rubber than that of unmodified DM, and the tensile properties of RTV-silicone/DM/PEI/MWCNT composites were improved compared to pure RTV-silicone.

3D-printing finds increasing applications including the dental implant. We report in this study a nicely printed and then cured composite consisting of nano-ceramic and photosensitive resin, targeting oral prosthesis application. The results show that the 3D-printed material has good geometry accuracy and satisfactory hardness, justifying its potential as an advanced manufacturing methodology for future dentistry.

The zinc metal anodes in aqueous zinc-ion batteries suffer from low cycling performance caused by uncontrolled dendrite. We have designed sulfonated poly-ether-ether-ketone (SPEEK) polymers as a surface coating layer on the zinc anode for dendrite suppression, in which the sulfonic groups in polymers act as effective active sites for zinc-ion diffusion. In SPEEK, the un-sulfonated domain serves as the framework and the sulfonated domain serves as the functional part to re-distribute the zinc ions. By optimizing the degree of SPEEK sulfonation, the best zinc anode coating has been achieved to present a high reversibility of over 1600 hours in symmetric cells and improved performance in full cells.

A high loading of Mn(ii)-metalated porphyrin was achievable in a 2D porphyrin-based Mn-MOF induced by an ionic liquid. The excellent stability, sufficient redox potential, atomically dispersed porphyrin Mn(ii) sites, desired CO2 affinity, high visible light-harvesting and efficient charge separation, endow this MOF with the overall photocatalytic conversion of CO2 to CH4 in gas-solid conditions.

Spinel-type materials are promising for the cathodes in rechargeable aqueous zinc batteries. Herein, Zn3V3O8 is synthesized via a simple solid-state reaction method. By tuning the Zn(CF3SO3)2 concentration in electrolytes and the cell voltage ranges, improved electrochemical performance of Zn3V3O8 can be achieved. The optimized test conditions give rise to progressive structure evolution from bulk to nano-crystalline spinel, which leads to capacity activation in the first few cycles and stable cycling performance afterward. Furthermore, the energy storage mechanism in this nano-crystalline spinel is interpreted as the co-intercalation of zinc ions and protons with some water. This work provides a new viewpoint of the structure evolution and correlated energy storage mechanism in spinel-type host materials, which would benefit the design and development of next-generation batteries.

Amorphous Ni–Fe hydroxides (NiFe(OH)x) are considered to possess promising potential as oxygen evolution reaction (OER) electrocatalysts, but amorphous NiFe(OH)x is hard to synthesize due to the co...

Computer-controlled dual-rotor polishing, as the final step to correct the optical part surfaces, plays an important role in improving the quality and service life of the surfaces. However, in previous study, the material removal model of dual-rotor polishing was fixed-point polishing model, which could not continuously polish the workpiece. Herein, a novel material removal model of dual-rotor polishing is proposed according to the removal profile orthogonal to the tool path. Firstly, the material removal function per unit time is developed, which is further converted into the material removal function per unit length of the tool path. Secondly, for obtaining the removal profile of dual-rotor polishing, the above function is integrated along the tool path in the polishing area. Then, to verify the effectiveness of the material removal model, the polished profile is studied experimentally and the effects of parameters, such as eccentricity, speed ratio, and main motion feed rate, on material removal of dual-rotor polishing are theoretically analyzed. It is demonstrated that the experimental material removal profiles are in good agreement with the theoretical results; besides, the stable and efficient polishing process can be obtained by optimizing parameters, which have different effects on the material removal depth. This work is of great significance for correcting the optical surface.

As the final step to fabricate the optical parts, the deterministic polishing process is usually used to reduce the roughness and correct the surface form. In this article, a new compensation metho...

Plasma-photocatalysis system (PPS) constructed by dielectric barrier discharge and TiO2 photocatalysts could realize toluene oxidation removal at low temperatures, but requires further enhancement in the performance due to the relatively poor activity of TiO2. We herein report that co-loading Ag and CeO2 on porous TiO2 can construct a active Ag–CeO2/TiO2 photocatalyst for the PPS, enabling the PPS to achieve promoted toluene conversion, CO2 selectivity and stability in toluene oxidation removal. The Ag–CeO2/TiO2 photocatalyst with porous microstructure and dispersed surface Ag particles can change the discharge mode, facilitating the interaction of plasma and photocatalysts in the PPS. We further disclose that the Ag/oxide interface can create highly active sites for surface oxidation reactions and enhances the separation of photoinduced electron-holes under the action of plasma. The intimate interaction between plasma and Ag–CeO2/TiO2 photocatalyst and enhanced surface/photocatalytic oxidation reactions on Ag/oxide interface result in the promoted performance of toluene oxidation. The creation of highly active metal/oxide interface on porous TiO2 photocatalyst may provide a strategy for the construction of high-efficiency PPS for VOCs removal.

Cobalt-free Li-rich Mn-based cathode materials are considered to be the next generation of Li-ion batteries due to low cost, high discharge capacities and high safety feature. However, there are still several serious issues that need to be solved urgently, such as low initial coulombic efficiency, low rate capability, poor cycling performance and voltage fading. Na doping or substitution is introduced to improve the electrochemical performance of Li1.2Mn0.6Ni0.2O2 cathode material, which is synthesized by sol-gel method. The effect of Na doping or substitution on the morphological, structural and electrochemical properties was systematically studied and analyzed by scanning electron microscope (SEM), X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cell test system and electrochemical workstation. These results illustrate that lattice layer spacing is enlarged by Na doping or substitution, which is beneficial for the diffusion of Li-ion, and the voltage fading is successfully suppressed. The best electrochemical properties were obtained when Na doping, which is attributed to the stronger structural stability and better reversibility of Li+ during the initial charge and discharge process.

This article aims to investigate the low-velocity impact behaviour of non-symmetric FMLs bonded with aluminium sheets and carbon fibre composite laminates by experimental and numerical methods. Two...

Bimetallic and polymetallic oxide-modified activated coke (AC) prepared by a one-step blending method and its desulfurization application were studied in this work. The bimetallic and polymetallic ...

This work mainly investigates the effects of the hole number and layer direction on the tensile mechanical behavior and failure mechanisms of multihole fiber metal laminates by experimental and numerical methods. With the aid of digital image correlation technique, tensile tests are implemented to obtain mechanical responses of different multihole fiber metal laminates. Subsequently, numerical simulation considering thermal residual stress is conducted to elucidate the failure modes and progressive damage evolution of multihole fiber metal laminates, which integrates the progressive damage model of composite laminates and a cohesive zone model between aluminum sheet/composite laminates. Finally, numerical predictions are found in a good agreement with experimental measurements, in terms of mechanical responses and fracture morphologies. Results demonstrate that the number of holes has negligible influence on the ultimate tensile strength, whereas affects the final failure strain of multihole fiber metal laminates evidently. With the increase of layer direction, the fracture morphology changes from evident brittle fracture to fiber pull-out and matrix damage, which indicates that the critical failure mechanism of multihole fiber metal laminates changes from tension dominated to tension–shear dominated. Additionally, the longer loading history from initial damage to final failure of composite laminates demonstrates the significance of considering progressive damage behavior in numerical simulation.

A series of aluminum and nickel (Al–Ni) co-doped LiAl0.15NixMn1.85−xO4 composites are prepared through a facile solid-state combustion method. All the as-obtained materials show a spinel structure and analogous spherical morphology with uniform particle distribution. Moreover, the synergistic merits of Al and Ni dual substitutions endow the spinel LiMn2O4 with an elevated Mn average valence state of 3.59 and relatively alleviative Jahn–Teller distortion. Among these samples, the LiAl0.15Ni0.03Mn1.82O4 (LANMO-0.03) cathode exhibits an optimal electrochemical performance with the discharge capacities of 103.3 mAh g−1 and 102 mAh g−1 at 1 C and 5 C in the first cycle, and the capacity retentions are 72.0% and 68.6% after 1000 cycles, respectively. Even at 1 C and high temperature of 55 °C, an excellent capacity retention remained to be 76.6% after 200 cycles. Furthermore, the LANMO-0.03 has good Li+ diffusion capability during charge/discharge, the DLi+ value of the LANMO-0.03 (1.65 × 10–11 cm2∙s−1) is higher than that of the LiAl0.15Mn1.85O4 (LAMO) (8.12 × 10–12 cm2∙s−1), and the charge transfer resistances of the LAMO and LANMO-0.03 samples are almost the same at 150 Ω before cycling but decrease to 130 Ω and 95 Ω after 1000 cycles at 1 C, respectively. These results demonstrate that the Al–Ni co-doped strategy can enhance the structural stability and provide stable Li+ diffusion channel during the long cycles even at elevated temperature. Meanwhile, the facile solid-state combustion approach can also be extended to the preparation of other dual cation-doped electrode materials.

In this work, we design oxygen vacancy-rich BiOBr:Yb3+/Er3+ (BYE-OV) ultrathin nanosheets, which can effectively enhance UC luminescence by oxygen vacancy engineering. Density functional theory calculations and UV-Vis-NIR absorption spectra reveal that the existence of oxygen vacancies leads to the formation of an intermediate band (IB) in the bandgap, which can enhance the light absorption ability and promote electron excitation and bandgap transitions (VB → CB, VB → IB and IB → CB), thereby providing the transfer of abundant electrons from the host to Er3+ ions. As a result, the emission intensity of green and red is exceptionally enhanced by 6.5 and 12 times respectively via introduced oxygen vacancies. Meanwhile, BYE-OV exhibits superior photocatalytic activity for the degradation of RhB under visible-NIR light irradiation. The enhanced activity can be mainly ascribed to enhanced photoabsorption in the visible-NIR region and improved UC luminescence. This work offers a new strategy for a rational design for enhancing UC luminescence, which has potential for applications in visible-NIR light photocatalysis.

A new hybrid organic-inorganic film, tincone, was developed by using molecular layer deposition (MLD), and exhibited high electrochemical activity toward Li storage. The self-limiting growth behavior, high uniformity on various substrates and good Li-storage performance make tincone a very promising new anode material for 3D microbatteries.

Exploiting near-infrared (NIR) light responsive photocatalysts is especially significant for effective use of solar energy. Enhancing the luminescence of upconversion (UC) photocatalysts is particu...

3D porous structural materials are proved to be enticing candidates for the fabrication of high-performance organic phase change materials (PCMs), but the stringent fabrication process and poor processability greatly hampered their commercialization. Herein, flexible leakage-proof composite PCMs with pronounced comprehensive performance are fabricated by a scalable polymer swelling strategy without using any solvent, in which the paraffin wax (PW) segment is confined in a robust flexible 3D polymer network, giving rise to the composite PCMs with excellent form stability even at 160 °C, a high latent heat energy storage density of 133.6 J/g, and an outstanding thermal conductivity of up to ∼5.11 W/mK. More importantly, the mass production of the flexible composite phase change fiber, film, and bulk products can be achieved by adopting mature processing technologies. These resultant composite PCMs exhibit promising thermal management ability to solve the overheating problem of electronics and high-efficiency solar-thermal energy conversion capacity.

In this article, a novel Al–6Y–2P master alloy with YP particles was successfully synthesized. By means of the fracture surface observation, it was found that YP particles with an average size of 21.5 μm exhibit the cubic morphologies. With the addition of Al–6Y–2P master alloy, primary Mg2Si particles in Al–Mg2Si composites can be significantly refined to 21.2 μm and 20.3 μm after holding for 30 min and 120 min respectively. Meanwhile, the morphologies of eutectic Mg2Si alter from a flake-like to fine fibrous shape. The reason for the excellent refining performance of this master alloy was discussed based on the chemical kinetics theory. During the solidification process, P atoms distribute homogeneously in the Al melt and precipitate in the form of AlP, providing heterogeneous nucleation sites for primary Mg2Si.

High-capacity silicon (Si) is recognized as a potential anode material for high-performance lithium-ion batteries (LIBs). Unfortunately, large volume expansion during discharge/charge processes hinders its areal capacity. In this work, we design a flexible graphene-fiber-fabric (GFF)-based three-dimensional conductive network to form a binder-free and self-standing Si anode for high-performance LIBs. The Si particles are strongly wrapped in graphene fibers. The substantial void spaces caused by the wrinkled graphene in fibers enable effective accommodation of the volume change of Si during lithiation/delithiation processes. The GFF/Si-37.5% electrode exhibits an excellent cyclability with a specific capacity of 920 mA h g-1 at a current density of 0.4 mA cm-2 after 100 cycles. Furthermore, the GFF/Si-29.1% electrode exhibits an excellent reversible capacity of 580 mA h g-1 at a current density of 0.4 mA cm-2 after 400 cycles. The capacity retention of the GFF/Si-29.1% electrode is up to 96.5%. More importantly, the GFF/Si-37.5% electrode with a mass loading of 13.75 mg cm-2 achieves a high areal capacity of 14.3 mA h cm-2, which outperforms the reported self-standing Si anode. This work provides opportunities for realizing a binder-free, flexible, and self-standing Si anode for high-energy LIBs.

The effects of cement dosage, compaction coefficient, molding method (vertical vibration method and static pressure method), and dry–wet and freeze–thaw cycles on the mechanical strength of cement-improved loess (CIL) were studied to reveal its strength degradation law under dry–wet and freeze–thaw cycles. Results show that when using the vertical vibration molding method, the strength degradation effect of CIL can be improved by increasing the cement dosage and compaction coefficient; however, it is not obvious. Under the action of dry–wet cycle, damages, such as voids and cracks of CIL, develop continuously. Further, the strength deteriorates continuously and does not decrease after more than 15 dry–wet cycles. Therefore, the dry–wet cycle degradation system is selected by considering the most unfavorable conditions. In the process of freeze–thaw alternation, the pores and fissures of CIL develop and evolve continuously and the strength deteriorates continuously under the joint influence of water and low temperature. The strength tends to become stable after more than 12 freeze–thaw cycles. According to the safety principle, the deterioration coefficient of the freeze–thaw cycles is 0.3.

We report a laser heterodyne radiometer (LHR) using a distributed feedback (DFB) diode laser operating in the near infrared region as the local oscillator to continuously measure atmospheric carbon dioxide (CO2) column concentration, which has a spectral resolution of 0.09 cm−1. The measurements for three consecutive days show that the averaged CO2 column concentration are 411.5 ppm, 410.4 ppm and 409.5 ppm, respectively. The averaged measurement precision is 1.6% by analyzing the standard deviation of CO2 column concentration. The relative error of 0.3% is estimated by comparing to CO2 average column concentration derived from GOSAT data on October 31, 2018 during the same measurement period. Moreover, the CO2 results are in good agreement with those measured by the ground-based Fourier transform spectrometer (FTS) simultaneously. The results prove the capacity and the reliability of the developed near infrared LHR to monitor the time series of regional CO2.

In view of the gradual promotion of Single Fuel Concept in the military field and also the rotary engine (RE) which has been widely applied in specialized equipment, it is necessary to study the basic spray characteristics of aviation kerosene under RE operation conditions and optimize the fuel injection strategies. In this research, an optically visible constant volume combustion chamber platform for Mie-scattering and a validated three-dimensional dynamic simulation model of aviation kerosene fueled direct injection rotary engine (DI-RE) were established. The experimental results show that the ambient temperature and pressure affect the spray process differently. There is no linear relationship between ambient temperature and penetration length. The ambient temperature of 600 K is a watershed, when it is below 600 K, the penetration length increases as the temperature rises. When the temperature reaches 600 K, the penetration length decreases rapidly which means a prominent improvement of atomization quality. On the basis of experimental results, the simulation was carried out and the results show that different injection strategies have important effect on distribution of fuel in cylinder, the larger injection angle will promote the atomization of fuel due to the collision between the spray and air flow field. In Case A3, B2 and C2, the fuel mainly distributes near the spark plugs in the center of the combustion chamber, which is supposed to be more conducive to the ignition and diffusion combustion process of the fuel.

A copper-modified activated coke (AC-Cu) was prepared through a developed one-step carbonization-activation blending (OCAB) method in which activation (900 °C) occurred just behind carbonization (6...

In this work, a new dynamic and a new static method for testing shear modulus of oriented strand board (OSB) are proposed, respectively. ANSYS software was used to calculate the mode shape coefficient of the OSB free plate and cantilever plate specimens, and the relationship of the mode shape coefficient depending on the length-to-width and the width-to-thickness ratios of the plate specimen was given. According to the stress and strain analysis of static torsion of the square plate, the principle of static square-plate torsional test for testing the shear modulus of orthotropic materials was described and the scheme of pasting the strain gauges in the direction of ±45° was proposed to ensure the accuracy of testing static shear modulus of OSB. The correctness of the new method for dynamically testing OSB shear modulus was verified by static square-plate torsional test. The longitudinal elastic modulus Ex, transverse elastic modulus Ey, elastic modulus in the 45° direction E45°, shear modulus in the plane Gxy and shear modulus in the 45° direction G45° were measured dynamically. The measured results of Ex/Ey = 2.88 and G45°

As a useful strategy, defect engineering is often used for structure design to produce desirable defect-rich crystal plane through crystal cracking process. Here, defect engineering successfully induces the defined and fragmented growth of MoS2 crystal lattice, ultimately promoting the in situ growth of MoS2 nanomaterials on the as-prepared free-standing Ti/TiO2 nanowires (TiO2 NWs). Present results also confirmed that, the shape of MoS2 nanomarterials could be controlled through precursor concentration, and the post-crystallization treatment of TiO2 NWs/MoS2 nanomaterials reduce the onset potential and catalytic current density over hydrogen evolution reaction activity test. By taking advantage of the excellent photoresponse performance of the near-infrared Zn doped CuInSe2 quantum dots, the composite photocatalyst with configuration of TiO2 NWs/MoS2 QDs/ZCISe QDs displayed good photocatalytic activity for the efficient removal of Cr(VI) within 120 min and evolution of hydrogen.

A novel industrial lithium-containing wastewater depth concentrating process integrating reverse osmosis (RO) and electrodialysis (ED) into a system is presented. A systematic analytical study was accomplished to optimize the studied parameters and minimize the energy consumption. The tested parameters were as follows: RO recovery by adding pressure, ED voltage drop, the concentration of RO retentate in ED feed solution, ED volume ratio, and ED operating mode. By using RO retentate instead of initial wastewater in the ED process, water energy consumption was reduced by 3.41 times from 26.67 to 7.81 kW h/m3, while optimizing the RO retentate concentration for the ED feed solution reduced the cost to 0.47 $/kg. The results showed that RO is crucial to preconcentrate lithium salt and save energy. Furthermore, the final LiCl concentration can approach as high as 87.09 g/L with the secondary ED process (Vd:Vc = 3:1), while the energy consumption can be saved as 7.71 kW h/m3 when the experiments stopped in regi...

Lanthanide luminescence nano-thermometers, with great potential applications in photo-thermal therapy for temperature detecting and controlling, have aroused wide interest recently. Enhancing the sensitivity and accuracy of temperature sensing property of those nano-thermometers are of great importance. In the present paper, NaGdF4 upconversion nanoparticles with high doping Bi ions concentration were investigated. With as high as 60% Bi ions doping concentration, no impurity phase was observed in the products and no morphological change occurred. Enhanced upconversion luminescence and thermal sensing properties were obtained, due to the tailoring of crystal field and increasing asymmetry of host matrix. Judd-Ofelt calculation was performed to testify the increasing lattice asymmetry, which was consistent with experimental results. This work provides guidance of tuning thermal-sensing properties of optical nano-thermometer, which are of great significance in bio-sensing field.

In this report, we describe flower-like VO₂(B)@C nanostructures, which exhibit spherical particles on radially protruding nanorods and are synthesized through a mild hydrothermal approach. Improved electrochemical performance can be easily acquired by controlling the amount of the sucrose. When the amount of sucrose is 0.32 g, the first discharge capacity of VO₂(B)@C nanostructures reaches 238.9 mAh g-1. At a high current density of 2000 mA g-1, flower-like VO₂(B)@C nanostructures exhibit 2.5-fold higher capacity than VOX without sucrose. As the rate is reduced to 100 mA g-1, a high discharge capacity of 144.4 mAh g-1 (79% of the original capacity) is recovered, manifesting good rate reversibility. This performance is derived from the unique flower-like structural feature with low crystallinity, which could significantly suppress irreversible Li+ trapping and improve Li+ diffusion kinetics. The well discharge capacity and capacity retention show that VO₂(B)@C has considerable potential for use in industry applications.

Particulate matter (PM) pollution has brought about severe threats to public health nowadays. PM2.5, referring to particles with an aerodynamic diameter smaller than 2.5 μm, is the most common form...

The glutathione (GSH) and mercaptopropionic acid (MPA) modified internal defect-rich, surface defects-poor near infrared (NIR) Zn–CuInSe2 (ZCISe) QDs were synthesized. Nanoporous ZnO nanosheets (NS) were firstly loaded with those ZCISe QDs to improve photoelectrochemical response in the NIR light region. Then loading Mn doping CdS thin film onto the ZCISe/ZnO NS was further used to reduce the interfacial recombination between different components of hybrid photoelectrode, in addition to enhance the light absorption and resist the photo-oxidation decomposition of the photocatalysts. Successively introducing ZCISe and Mn–CdS onto ZnO NS can increase the photocurrent intensities from 1 mA/cm2 for naked ZnO NS, 2.2 mA/cm2 for ZCISe/ZnO NS, to 9 mA/cm2 for Mn–CdS/ZCISe/ZnO NS. Here, excellent performance of ZCISe based ZnO NS photoelectrode is mainly attributed to an intrinsic defect state-related donor–acceptor pair (DAP) in ZCISe QDs with long-lived photogenerated carriers. Photocatalytic properties of Mn–CdS/ZCISe/ZnO NS were evaluated by removing azo dyes with an efficiency of 83%, an enhancement of 97% compared to that of ZnO NS.

Supercapacitors based on two-dimensional (2D) ultrathin nanomaterials of reduced graphene oxide (rGO) and vanadium pentoxide (V2O5) are rapidly growing, but constructing three-dimensional (3D) skeleton networks structure with both high energy density and superior cycle stability remains challenging. In this work, supercapacitor based on 3D skeleton networks of rGO nanosheets/V2O5 nanobelts hybrids has been successfully constructed via a simple one-pot hydrothermal method. The resultant rGO/V2O5 hybrid aerogel electrodes show a high specific capacitance of 310.1 F g−1 (1 A g−1) and 195.2 F g−1 (10 A g−1). Moreover, the assembled symmetric supercapacitors based on as-fabricated hybrid electrodes deliver a high gravimetric capacitance of 225.6 F g−1 (0.5 A g−1), a high energy density of 31.3 Wh kg−1 (249.7 W kg−1) and excellent long-term cycle stability (remain 90.2% after 5000 cycles). Above all, the as-designed 3D skeleton networks, with rGO nanosheets and V2O5 nanobelts hybrids intimately stacked, can give a guidance for designing other high-performance graphene-based electrodes and hold a great potential for high-performance electrical energy storages.

Open in a separate window H3PO2 has emerged as an indispensable reducing agent for electroless nickel plating. Commercial preparation of H3PO2, with high purity and low cost, is a great challenge. In this work, a novel technique by the integration of bipolar membrane electrodialysis (BMED) with ion-exchange absorption was designed to prepare high-quality H3PO2 aqueous solution. The critical parameters, such as voltage drop, NaH2PO2 concentration, and different types of anion-exchange membranes, were systematically investigated. Continuous experiments indicated that a high yield of up to 80.06% with a low energy consumption of 4.99 kW h/kg was achieved under optimal operation conditions (voltage drop of 20 V, feed concentration of 15 wt % NaH2PO2, and anion-exchange membrane of AHA). Moreover, leakage of Na+ ions through the bipolar membrane was observed. By using T-52H cation-exchange resin, the final concentration of Na+ ions in H3PO2 aqueous solution was reduced to 20.91 mg/L. Subsequently, a long-term experiment was performed to evaluate the stability of the BMED stack, and the concentration of H3PO2 in the acid compartment reached 4.15 mol/L. Under optimal conditions, the H3PO2 production cost was estimated at $0.937 kg–1, which was competitive and economically friendly for industrial application.

It is an urgency to find capable lead-free piezoelectric ceramics to show effort towards environmental protection. Bi0.5Na0.5TiO3 (BNT)-based piezoelectric ceramics is one of the most promising lead-free systems, for which compositional modification is an efficient way to enhance the piezoelectric performance. In this work, lead-free 0.82(Bi0.5Na0.5)TiO3-(0.18-x)BaTiO3-x(Bi0.5Na0.5)(Mn1/3Nb2/3)O3 ceramics were synthesized by a conventional solid state reaction method. Polarization and strain hysteresis loops implies a phase transition from FE (ferroelectric phase) to ER (ergodic relaxor). An electric field induced high strain of 0.28% occurred at x = 0.0275, which was attributed to the coexistence of FE and ER phases. It is considered that our work can help to understand the complex phenomenon observed in BNT-based lead-free system.

Exploring the thermometric properties of UCNPs is of great importance for non-contact fluoresce thermometers. Ln-doped β-NaGdF4:Yb3+,Er3+ upconversion nanoparticles (UCNPs) have been fabricated by varying the ratio of citric ions to molecules in precursor. Morphology of the as-prepared β-NaGdF4:Yb3+,Er3+ UCNPs turns from hexagonal prisms to agglomerations of smaller particles with decreased dimension. Luminescence intensity decreases and red-to-green ratio increases with increasing ratio of citric ions to molecules. A dual-mode thermometric property has been found in the as-prepared β-NaGdF4:Yb3+,Er3+ UCNPs. The first mode derives from the temperature dependent fluoresce-intensity-ratios of thermally coupled manifolds of Er3+ (2H11/2) and (4S3/2) manifolds, of which the maximum relative sensitivity value is 0.0036 K−1. The other mode derives from temperature dependent red-to-green ratios, which is a linear function of temperature and the maximum relative sensitivity value is 0.0238 K−1. The β-NaGdF4:Yb3+,Er3+ UCNPs with morphology of agglomerations of smaller particles with high surface-to-volume ratios show advanced sensitivities, which are suitable for noncontact optical thermometer.